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Importance of electron distribution profiles to chorus wave driven evolution of Jovian radiation belt electrons 被引量:2
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作者 Jing Huang XuDong Gu +4 位作者 BinBin Ni Qiong Luo Song Fu Zheng Xiang wenxun zhang 《Earth and Planetary Physics》 2018年第5期371-383,共13页
Wave-particle interactions triggered by whistler-mode chorus waves are an important contributor to the Jovian radiation belt electron dynamics. While the sensitivity of chorus-driven electron scattering to the ambient... Wave-particle interactions triggered by whistler-mode chorus waves are an important contributor to the Jovian radiation belt electron dynamics. While the sensitivity of chorus-driven electron scattering to the ambient magnetospheric and wave parameters has been investigated, there is rather limited understanding regarding the extent to which the dynamic evolution of Jovian radiation belt electrons, under the impact of chorus wave scattering, depends on the electron distribution profiles. We adopt a group of reasonable initial conditions based upon the available observations and models for quantitative analyses. We find that inclusion of pitch angle variation in initial conditions can result in increased electron losses at lower pitch angles and substantially modify the pitch angle evolution profiles of > ~500 keV electrons, while variations of electron energy spectrum tend to modify the evolution primarily of 1 MeV and 5 MeV electrons. Our results explicitly demonstrate the importance to the radiation belt electron dynamics in the Jovian magnetosphere of the initial shape of the electron phase space density, and indicate the extent to which variations in electron energy spectrum and pitch angle distribution can contribute to the evolution of Jovian radiation belt electrons caused by chorus wave scattering. 展开更多
关键词 Jovian radiation belt whistler-mode chorus wave-particle interactions electron distribution profile
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A novel broadband and high-gain microstrip reflectarray antenna with variable polarization 被引量:1
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作者 Zhihang WU wenxun zhang +1 位作者 Zhenguo LIU Wei SHEN 《Frontiers of Electrical and Electronic Engineering in China》 CSCD 2008年第1期86-89,共4页
This article proposes a new kind of microstrip reflectarray antenna,of which the polarization could be reconfigured among all the polarization states instead of some fixed states in a dual-or multi-polarized antenna.T... This article proposes a new kind of microstrip reflectarray antenna,of which the polarization could be reconfigured among all the polarization states instead of some fixed states in a dual-or multi-polarized antenna.The mechanism for polarized variability is so simple that only mechanical rotation is needed.Theoretical analysis shows that the reflected polarization covers all states and that the dual-or multi-layered unit structure sandwiched with air-gaps can broaden the bandwidth efficiently.Moreover,it is demonstrated that adopting more elements can enhance antenna gain.With these advantageous features,this kind of antenna has the potential significance for engineering applications in radar,communication,etc.In this article,a complete theoretical analysis as well as a specific design sample is given to verify this method. 展开更多
关键词 REFLECTARRAY variable polarization polarization reconfigurable antenna WIDEBAND HIGH-GAIN
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